Only teenagers can save the planet!

'Make no mistake, this is the first century since our caveman days in which Homo sapiens could be terminated. Even if Homo sapiens survives, civilisation may not."

James Martin, the author responsible for these words, is clearly a worried man. He believes humanity is racing at breakneck speed into an era of extremes - of poverty and wealth, of religious confrontation, of globalisation and technological advance. At their confluence is an almighty car crash that may not only wipe out humanity, but leave the planet a bit tatty for all we leave behind. To survive is going to take a Herculean effort, he says.

Martin sets out his view of the dangerous rapids ahead in a bright yellow tome published today, The Meaning of the 21st Century: a vital blueprint for ensuring our future. His words will be listened to. You may not have heard of him, but Martin is a world authority on the impact of technology on society and is admired by the likes of Sir Martin Rees, the president of the Royal Society. The author of the Pulitzer-nominated The Wired Society, that foresaw the internet world, Martin is a physicist turned futurologist with honorary doctorates from all six continents. He was a scientific adviser to the US Department of Defence and gave £60m to Oxford University to set up a department that bears his name.

Martin believes that salvation from imminent doom can only to be found in today's teenagers. He calls the clever and concerned among them the "transition generation". During their lifetime, he says, fresh water will run out in many parts of the world, making food production difficult. Fish will become too rare to replenish themselves. Global warming will bring hurricanes stronger than Katrina. And tensions from extremism, religious belligerence and suicidal terrorism will coincide with technological advances that see genetically modified viruses developed as weapons.

For Martin, the forthcoming decades are a white-water raft ride. "Things are going to get more and more turbulent as we go along, and the dangers will get more severe," he says. As time goes by the chances of disaster become ever more probable. "The job of the transition generation is to get humanity through the canyon with as little mayhem as possible into what we hope will be smoother waters beyond," he writes. A strong message is the need to become "eco-affluent", a dramatic shift in primarily western lifestyles so that we can consume without destroying the planet.

It is unlikely that progress will be made without catastrophe, Martin believes. Just as Thalidomide forced stricter drug testing, so further disasters will drive future changes.

Martin got a lot right in The Wired Society, and sold enough copies to buy a sportscar and a Bermudan island. His latest read may be similarly popular, if less jolly. "If we understand this century and learn how to play its very complex game, our future will be magnificent. If we get it wrong, we may be at the start of a new type of Dark Age".